Individuals using audio systems in vehicles generally do so for music enjoyment and/or for voice communication. The vehicle operator is typically immersed in the audio experience when using such devices. The acoustic signals produced from these devices may contend with background noise from the external vehicle environment (e.g., road, engine, wind and traffic noise), as well as noise from the internal vehicle environment (e.g., heating and ventilation noise) in order to be audible. As the background noise levels change, the operator may need to adjust the volume, in order to listen to their music over the background noise. Alternatively, the level of reproduced audio may be automatically increased, for example, by audio systems that increase the audio level as the vehicle velocity increases (i.e., to compensate for the rise in noise level from road, engine, and aerodynamic noise). One example of such an automatic gain control system is described in U.S. Pat. No. 5,081,682.